Sudoku: Maths Puzzle or Logic Puzzle?

A question that comes up with some frequency is whether sudoku is a maths puzzle or a logic puzzle, and depending where you look, you can see it referenced as falling in both these genres.

Infact, sudoku is purely a logic puzzle.

The reason for this is that when solving the puzzle you only use logic, you do not use any maths at all.

At first glance, it is understandable why it might be thought that it is a maths puzzle: because the grid contains numbers, and usually we use numbers to do maths.

However, in this instance the numbers are there as symbols only - we do not use the fact that 9 is greater than 7, for instance, when solving sudoku, unlike a puzzle like kakuro where we do use the properties of numbers to solve the puzzle.

Indeed in sudoku the numbers could be, and sometimes are, replaced with letters, and the puzzle functions exactly the same way. Similarly they could be replaced with colours, pictures of fruits, Egyptian hieroglyphs or any other set of nine clearly different marks that you choose to come up with.

And it is because of this that ordinary sudoku is very much a logic puzzle and not a maths puzzle. Date written: 26 Nov 2010